We have no eternal allies, and we have no perpetual enemies. Our interests are eternal and perpetual, and those interests it is our duty to follow.” Thus did Lord Palmerston, British prime minister from 1855 to 1858 and 1859 to 1865, describe his country’s foreign policy at the apogee of its global power.Donald Trump is a Palmerstonian, as a former senior official at the US state department advised me last week. If any coherent doctrine underlies the president’s assault on the world order his own country created, that is it. But Mr Trump is no Palmerston and the early 21st century is not the middle of the 19th. Mr Trump’s narrowly transactional approach, driven by ignorance and resentment, risks disaster.The US took a very different view in the aftermath of the second world war. The jockeying for position among mutually suspicious and nationalistic great powers had led to two shattering world wars. These had left Europe prostrate. No rationally founded idea of “interest” could justify this dire outcome. The world needed a much more enlightened vision of international relations than this one had been.The new vision contained three essential elements. First, having been dragged out of its isolationism by two world wars, the US would become the stabilising power. Second, the US would form eternal alliances built on shared values. Finally, a set of international agreements, initially mostly economic, subsequently extended into areas such as climate, would provide a predictably liberal global economy and the capacity to tackle global challenges. All this, US policymakers believed, embodied a rational view of US interests. Its power was to be allied to beneficial ends by novel and intelligent means.The US has made big mistakes: above all, trusting too much in the efficacy of interventions, especially military intervention, in other countries. Yet, overall, the Pax Americana has been a period of great success. The resurgence of world trade helped deliver an unparalleled era of global prosperity. The political and economic successes of the west gave victory over Soviet communism. Despite China’s rise, the US and its allies still enjoy preponderant economic and military power. (See charts.)In the words of the King James Bible, “there arose up a new king over Egypt, which knew not Joseph”. That ignorant king is Mr Trump, who knows not those Americans who created the postwar order. He believes in transactions over alliances, bilateralism over multilateralism, unpredictability over consistency, power over rules and interests over ideals. He prefers authoritarians such as China’s Xi Jinping, Russia’s Vladimir Putin and even North Korea’s Kim Jong Un, to the leaders of his democratic allies. In his view, might makes right. Striking features of Mr Trump’s behaviour are his fabrications, self-pity and bullying: others, including historic allies, are “laughing at us” over climate or “cheating” us over trade. The EU, he argues, “was put there to take advantage of the United States, OK? . . . Not any more . . . Those days are over.” These are absurd claims. Armoured by ignorance and such attitudes, Mr Trump might do just about anything, particularly now, when he seems to be increasingly self-confident. The trade wars he is unleashing, under dubious justifications and for uncertain ends, lack clear outcomes. As Gavyn Davies notes, the cycles of retaliation might be prolonged. The costs of deglobalisation might be very high, especially if one includes the uncertainty it will create. Adam Posen, director of the Peterson Institute for International Economics, in Washington, notes the risk that these conflicts will “break down the separation between commerce and national security, raising the risk of significant escalation of conflict”. Mr Trump is deliberately confusing trade with national security. That has to make resolution far more difficult to achieve. Mr Trump’s attitudes to China and Europe now look the most momentous. If the US dissolves its commitment to Nato or uses all its might to break up the EU, the stresses upon the latter — and the incentive for Russia (or China) to meddle in it — could be huge: Europe might come together, or it might break apart. Again, Mr Trump is determined to challenge China’s rise. While some progress on trade issues is indeed possible, this broader objective is not one China could conceivably accept. Growing friction now looks inevitable. This, then, is an important historical moment. The foundations of the postwar economic and security order, not just of the “holiday from history” of the post-cold war era”, are now in doubt.The question is whether one should view this as a temporary, albeit perilous, departure from the normal state of affairs, or a far more permanent shift. The argument for the former is that Mr Trump is an exceptional figure, who came from nowhere, in special circumstances. When he passes, so will this upheaval. This may be a delusion. Unless he blows up the world economy, Mr Trump has a good chance of re-election and so may last for six-and-a-half more years. He has identified a large and resentful part of the US body politic whose state is unlikely to get any better, while the gerrymandering of the US vote is likely to get even worse. Not least, a growing number of Americans agree that China is a cheat and a threat and Europeans are carping freeloaders. Mr Trump will pass. Trumpism might not. The US could become far worse than soberly Palmerstonian. The rest of the world should take that possibility seriously — and think and act accordingly.

If you know the other and know yourself, you need not fear the result of a hundred battles.

Sun Tzu

We are travelers on a cosmic journey, stardust, swirling and dancing in the eddies and whirlpools of infinity. Life is eternal. We have stopped for a moment to encounter each other, to meet, to love, to share.This is a precious moment. It is a little parenthesis in eternity.